Staying mad is bad for your health, so here's how to learn to forgive

"Anger is an acid that can do more harm to the vessel in which it is stored than to anything on which it is poured." — Mark Twain

You know what it feels like to hold a grudge. Your stomach churns. Your muscles tense. Your mind clouds with anger, resentment and maybe even notions of revenge. And the longer it goes, the darker your thoughts become.

Though that bitterness can be understandable — and even justifiable — it comes with a price.

Studies show that depression, anxiety, cardiovascular issues, immune system problems, sexual dysfunction and a higher risk of stroke are all connected to letting hostility fester. As Twain says, it's an acid that harms your body.

But you can stop the damage with one simple act: forgiveness.

The act of forgiving — of truly letting go — creates a healthier body and mind. Research has found that when you forgive, you instantly reduce your blood pressure and lessen your destructive feelings. In the days and weeks that follow, you may experience:

"It's not always easy, but if you think of what we want in life, we want to be healthy, we want to be at peace, we want to be loved," says Everett Worthington, Professor of Psychology at Virginia Commonwealth University and a pioneer in forgiveness research. "If I forgive, it promotes all of those."

What is Forgiveness?

According to Worthington, there are two kinds of forgiveness.

Decisional forgiveness is largely behavioral, and directed toward the person who has done us wrong: "We make a decision about how we're going to act toward someone," says Worthington.

It's reconciliation, or an outward smoothing of a situation that can lead to a deeper forgiveness, but doesn't always.

Emotional forgiveness, on the other hand, is what Worthington describes as "emotionally replacing negative emotions like resentment, anger, bitterness, and hostility, with other, positive emotions…like empathy and sympathy, and compassion, and maybe even love."

It's not revenge, reconciliation, or simply forgetting something has happened. It's acknowledging your pain, and then letting it go. Your mental and physical well-being are affected, and even determined, by emotional forgiveness.

When it comes to personal relationships, emotional forgiveness is crucial to getting along, as well as each partner's long-term health.

"If I'm forgiving of what my partner does to hurt me, then she is more likely to be forgiving of me," says Worthington. In fact, one University of Miami study found that reciprocity was "strongly linked to well-being," while another report published in the journal Personal Relationships discovered that "conciliatory behavior" actually lowered the blood pressure of both parties during arguments.

Your ability to forgive yourself is another factor in healthy relationships. "If someone's holding a grudge against themselves," says Worthington, "that tends to produce regret, remorse, sorrow, shame and guilt. So it's a different set of emotions, but one that can take a toll."

How Can I Forgive?

There's no single path to forgiveness; it's complex, personal, and differs for everyone. However, current research points toward three key steps that could help the process along:

1. Acknowledge what took place. Don't deny the event. Go over the facts in your mind as impartially as possible.

2. Choose to forgive and commit to that forgiveness. Give up your grudge, and absolve your perpetrator for good. Resist the temptation to dwell.

3. Move on. Release the toxic emotions that crowd out feelings like gratitude and love, once and for all.

What if we find we can't absolve someone? Ultimately, we must understand there are no benefits of holding on to anger. "I think we always should try to forgive. It's not only good for us, but it's a good thing to do," says Worthington., "Ask yourself, 'Why do I want to carry this grudge around?'"